Lead: either the physical piece of wire attached to the patient, or the final result of differentials.
V are unipolar leads. Put 0 to the minus lead of the voltmeter, which then allows for a reading of just the
limbs. Chest is covered with 6 leads. 12 leads are taken since they are all different. Each of the leads is
looking at the activity of the heart from different angles. The right arm unipolar lead would have an
inverted T wave.
Action Potentials: the ventricular muscles have much longer action potentials, lasting nearly 300ms.
Since K+ is high in the side at rest, the Nernst potential for K+ is dominant for the cell at rest. When
activated, Na+ floods the cell, and the Nernst potential pushes towards the Na+ potential. The I Na+fast
inward Na+ current follows as the permeability for sodium dramatically increases when activated. While
this is happening, the permeability of K+ drops. Then recovers as Na+ drops for repolarization. Calcium
acts as a chemical signal to spread the signal around. IcaL and IcaT (long term and transient).
The sinus node is never at rest. No membrane potential exists. Without turnover, cancer would rarely
take place, since mutati